Semiconductor member, semiconductor article manufacturing method, and led array using the manufacturing method

ABSTRACT

A novel semiconductor article manufacturing method and the like are provided. A method of manufacturing a semiconductor article having a compound semiconductor multilayer film formed on a semiconductor substrate includes: preparing a member including an etching sacrificial layer ( 1010 ), a compound semiconductor multilayer film ( 1020 ), an insulating film ( 2010 ), and a semiconductor substrate ( 2000 ) on a compound semiconductor substrate ( 1000 ), and having a first groove ( 2005 ) which passes through the semiconductor substrate and the insulating film, and a semiconductor substrate groove ( 1025 ) which is a second groove provided in the compound semiconductor multilayer film so as to be connected to the first groove, and bringing an etchant into contact with the etching sacrificial layer through the first groove and then the second groove and etching the etching sacrificial layer to separate the compound semiconductor substrate from the member.

TECHNICAL FIELD

The present invention relates to a semiconductor member and a method ofmanufacturing a semiconductor. The present invention also relates to anoptical device such as a light-emitting device, an LED array chip, anLED printer head, and an LED printer manufactured using such method.

BACKGROUND ART

There is known a technology in which a light-emitting diode forminglayer formed via an etching sacrificial layer on a GaAs substrate istransferred onto a silicon substrate.

A technology where a light-emitting diode forming layer is transferredonto a silicon substrate is described in Japanese Patent Laid-OpenApplication No. 2005-012034.

More specifically, first, a groove for dividing a light-emitting diodeforming layer formed via a sacrificial layer on a GaAs substrate intoits respective light-emitting regions is provided. The sacrificial layeris exposed immediately below the groove.

Then, a dry film resist is bonded to the light-emitting diode forminglayer. Further, a mesh support member formed of metal wire is bonded tothe dry film resist.

After that, the resist except that located immediately below the metalwire is removed. Then, the sacrificial layer is etched by bringing anetchant into contact with the sacrificial layer via the mesh supportmember, whereby the GaAs substrate is separated from the bondedstructure.

Further, after the GaAs substrate is separated, the light-emitting diodeforming layer is bonded to a silicon substrate.

In this way, a light-emitting diode forming layer is transferred onto asilicon substrate.

DISCLOSURE OF THE INVENTION

However, the inventors of the present invention have come to recognizethat, because the technology described in the above-mentioned JapanesePatent Laid-Open Application No. 2005-012034 requires a lot of bondingprocesses, when mass production thereof is considered, furthercontrivance is necessary.

The inventors of the present invention have come to think that, when thenumber of the bonding processes is decreased and the sacrificial layeris etched, it is desirable that the light-emitting diode forming layerbe transferred onto the silicon substrate, and achieved the epoch-makingpresent invention as described below.

An object of the present invention is as follows.

That is, an object of the present invention is to provide a novelmanufacturing method and a novel member materialized by bondingprocesses whose number is as small as possible.

According to the present invention, there is provided a method ofmanufacturing a semiconductor article having a compound semiconductormultilayer film formed on a semiconductor substrate, including:

preparing a member including an etching sacrificial layer, a compoundsemiconductor multilayer film, an insulating film, and a semiconductorsubstrate provided on a compound semiconductor substrate in the statedorder from the side of the compound semiconductor substrate, the memberhaving a first groove provided in the compound semiconductor multilayerfilm and a second groove passing through the semiconductor substrate andbeing connected to the first groove; and

bringing an etchant into contact with the etching sacrificial layerthrough the first groove and the second groove and thus etching theetching sacrificial layer to separate the compound semiconductorsubstrate from the member.

In this case, the member may be prepared by:

forming the etching sacrificial layer on the compound semiconductorsubstrate;

forming the compound semiconductor multilayer film on the etchingsacrificial layer;

forming the first groove in the compound semiconductor multilayer filmsuch that the etching sacrificial layer is exposed;

preparing the semiconductor substrate having the second groove and theinsulating film; and

bonding the compound semiconductor substrate to the semiconductorsubstrate such that the first groove and the second groove are connectedto each other.

Alternatively, the member may be prepared by:

forming the etching sacrificial layer on the compound semiconductorsubstrate;

forming the compound semiconductor multilayer film on the etchingsacrificial layer;

preparing the semiconductor substrate having the insulating film;

bonding the compound semiconductor substrate to the semiconductorsubstrate;

forming the second groove in the semiconductor substrate;

forming a third groove in the insulating film; and

forming the first groove in the compound semiconductor multilayer filmsuch that the etching sacrificial layer is exposed.

The semiconductor substrate may be provided with a driver circuit fordriving a light-emitting diode structured to include the compoundsemiconductor multilayer film.

Further, according to a second aspect of the present invention, there isprovided a method of manufacturing a semiconductor article formed bybonding a compound semiconductor substrate and a semiconductorsubstrate, comprising the steps of:

preparing the compound semiconductor substrate and the semiconductorsubstrate;

forming an etching stop layer, an etching sacrificial layer, a compoundsemiconductor multilayer film including an active layer, and a mirrorlayer on the compound semiconductor substrate in the stated order fromthe side of the compound semiconductor substrate;

providing a first groove in the compound semiconductor multilayer filmsuch that the etching sacrificial layer is exposed to divide thecompound semiconductor multilayer film in an island shape;

forming a second groove passing through the semiconductor substrate;

bonding the compound semiconductor substrate to the semiconductorsubstrate via an organic material film such that the second grooveprovided in the semiconductor substrate and the first groove areconnected to each other to form a member;

bringing the etching sacrificial layer into contact with an etchant toseparate the compound semiconductor substrate from the member; and

forming a light-emitting device using the compound semiconductormultilayer film on the semiconductor substrate.

According to a third aspect of the present invention, there is providedan LED array manufactured using the method of manufacturing asemiconductor article described above.

An LED printer head may be configured by mounting a rod lens array onthe LED array.

Further, according to another aspect of the present invention, there isprovided an LED printer including the LED printer head, a photosensitivedrum, and a charging unit, and an imaging unit for writing anelectrostatic latent image on the photosensitive drum with the LEDprinter head being as a light source.

In particular, a color LED printer may be formed by including aplurality of the imaging units.

Further, according to a fourth aspect of the present invention, there isprovided a semiconductor member having a compound semiconductormultilayer film formed on a semiconductor substrate, comprising anetching sacrificial layer, the semiconductor multilayer film, aninsulating film and a silicon substrate formed on a compoundsemiconductor substrate in the stated order from the side of thecompound semiconductor substrate, in which a groove for exposing theetching sacrificial layer is provided in the compound semiconductormultilayer film, and a passing-through groove being connected to thegroove is provided in the semiconductor substrate and the insulatingfilm.

Further, according to a fifth aspect of the present invention, there isprovided a method of manufacturing a semiconductor article including acompound semiconductor multilayer film on a substrate, including:

preparing a member including an etching sacrificial layer, a compoundsemiconductor multilayer film and a second substrate provided on a firstsubstrate in the stated order from the side of the first substrate, themember having a first groove provided onto the compound semiconductormultilayer film and a second groove provided passing through the secondsubstrate and being connected to the first groove; and

bringing an etchant into contact with the etching sacrificial layerthrough the first groove and the second groove and thus etching theetching sacrificial layer to separate the first substrate from themember.

Further, according to a sixth aspect of the present invention, there isprovided a method of manufacturing a light-emitting device including:

forming a separation layer and a light-emitting layer on a firstsubstrate in the stated order from the side of the first substrate;

bonding the first substrate to a second substrate such that thelight-emitting layer is positioned inside to form a bonded member;

transferring the light-emitting layer onto the second substrate byetching and removing the separation layer,

wherein a pair of the separation layer and the light-emitting layer onthe first substrate is repeatedly deposited n times, the n being anatural number of two or more, only the uppermost light-emitting layeris patterned into a shape of a plurality of islands, and then the firstsubstrate is bonded to the second substrate to form a bonded structure,

and wherein an etchant is caused to penetrate into a space which isformed in the bonded structure by the island-shape patterning, therebybringing the separation layer into contact with the etchant toselectively transfer the island-shaped light-emitting layer onto thesecond substrate.

Further, according to a seventh aspect of the present invention, thereis provided a light-emitting device including a light-emitting deviceformed on a silicon substrate via a DBR mirror.

Further, according to an eighth aspect of the present invention, thereis provided a semiconductor member, including a separation layer, acompound semiconductor multilayer film, an insulating film and a secondsubstrate provided on a first substrate, in the stated order from theside of the first substrate,

in which a groove for dividing the compound semiconductor multilayerfilm into a plurality of regions and for exposing the separation layeris provided in the compound semiconductor multilayer film, and apassing-through groove being connected to the groove is provided in thesecond substrate and the insulating film.

Further, according to a ninth aspect of the present invention, there isprovided a method of manufacturing a semiconductor article having acompound semiconductor multilayer film formed on a semiconductorsubstrate, including:

preparing a member including a separation layer, a compoundsemiconductor multilayer film, and a second substrate provided on afirst substrate in the stated order from the side of the firstsubstrate, the member having a first groove provided in the compoundsemiconductor multilayer film and a second groove provided passingthrough the second substrate and being connected to the first groove;and

separating the first substrate from the member.

Further, according to another aspect of the present invention, there isprovided a method of manufacturing an LED array, including:

forming a separation layer, a light-emitting layer, and a DBR layer inthe stated order on a surface of a first semiconductor substrate andbonding the substrate to a second substrate having a semiconductorcircuit formed thereon via an insulating film;

transferring the light-emitting layer and the DBR layer of the firstsubstrate onto the second substrate by etching and removing theseparation layer;

making the transferred light-emitting layer into an array of a pluralityof light-emitting portions; and

electrically connecting the plurality of light-emitting portions with anelectrode portion of the semiconductor circuit for controlling lightemission of the light-emitting portions.

Further, according to another aspect of the present invention, in thefirst aspect of the invention, the island-shaped compound semiconductormultilayer film formed on the compound semiconductor substratesurrounded by the first groove has a rectangle shape having a long sideand a short side, and a plurality of the second grooves passing throughthe semiconductor substrate are intermittently disposed in an array inparallel with the direction of the long side (longitudinal direction)thereof.

Further, according to another aspect of the present invention, in thefirst aspect of the invention, there is provided a method ofmanufacturing a semiconductor, after separating the compoundsemiconductor substrate from the member, an electrode is formed on theisland-shaped compound semiconductor multilayer film via an insulatingmember to form a light-emitting device array chip having a long sidedirection and a short side direction, and the second substrate is cut ina direction of the long side so that second passing-through grooves inparallel with one another which are provided in the second substrate andare arranged in the direction of the short side are connected to eachother.

Further, according to another aspect of the present invention, in thefifth aspect of the invention, the top view of the shape of the compoundsemiconductor multilayer film patterned in an island shape by the firstgroove is a rectangle having a long side direction and a short sidedirection, and a plurality of the second grooves passing through thesecond substrate is formed so as to be in parallel in the direction ofthe long side to thereby form a passing-through groove group in thedirection of the long side, in which a plurality of the passing-throughgroove groups in the direction of the long side is arranged so as to bein parallel with one another at intervals which are equal to or longerthan the length of the short side of the island-shaped compoundsemiconductor multilayer film.

Further, according to another aspect of the present invention, there isprovided a bonded structure formed by bonding a first substrate and asecond substrate; the first substrate including compound semiconductormultilayer film regions each patterned in an island shape on the firstsubstrate via a separation layer, in which a first groove is providedbetween the compound semiconductor multilayer film regions and the topview of the shape of the compound semiconductor multilayer film regionsis a rectangle having a direction of a long side and a direction of ashort side; the second substrate including a second groove passingthrough the second substrate, in which a plurality of the second groovesare intermittently provided so as to be in parallel in the direction ofthe long side to thereby form a passing-through groove group in thedirection of the long side, and a plurality of the passing-throughgroove groups in the direction of the long side are arranged so as to bein parallel with one another at intervals which are equal to or longerthan the length of the short side of the island-shaped compoundsemiconductor multilayer film regions.

Further, according to another aspect of the present invention, aplurality of the LED array chips manufactured by the above-describedmethod of manufacturing a semiconductor article are connected theretoand a rod array lens is not mounted.

It is to be noted that, in the above description, “in the stated order”means “in the stated order with regard to the listed structuralelement”, and does not preclude a case where another layer is providedbetween the listed layers.

EFFECT OF THE INVENTION

According to the present invention, the number of bonding processes canbe decreased compared with that of the technology described in JapanesePatent Laid-Open Application No. 2005-012034.

Further, with regard to the member formed by bonding the first substrate(for example, a compound semiconductor substrate) to the secondsubstrate (for example, a silicon substrate), the etchant is broughtinto contact with the sacrificial layer through the passing-throughgroove formed in the second substrate.

Therefore, compared with a case where the etchant is made to penetratein the direction of a surface of the substrate only from the most outerperipheral sides of the member, the time required for etching thesacrificial layer can be shortened.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a member in connection with a method ofmanufacturing a semiconductor of a first embodiment according to thepresent invention.

FIG. 2 is a view seen from below of a section 2-2 in FIG. 1.

FIG. 3 is a view illustrating a section 3-3 in FIG. 1.

FIG. 4 is a partially exploded perspective view illustrating apositional relationship between a first groove and a semiconductorsubstrate groove and illustrating a state where an island-shapedcompound semiconductor multilayer film is disposed between semiconductorsubstrate grooves.

FIG. 5 is a sectional view illustrating an exemplary structure where adriving circuit and an LED array are connected on a wiring substrate.

FIG. 6 is a view illustrating an LED printer head.

FIG. 7 is a sectional view illustrating a state where a driver circuitis built directly on the side of an Si substrate and is connected to anLED device.

FIG. 8 is a view illustrating a light-emitting device array circuit 8500which can be time-division driven for decreasing the number ofelectrodes.

FIG. 9A is a conceptual view illustrating an exemplary structure of anLED printer.

FIG. 9B is a conceptual view illustrating an exemplary structure of acolor printer.

FIG. 10 is a view illustrating an example of a method of manufacturing asemiconductor article according to the present invention.

FIG. 11 is a view illustrating the example of a method of manufacturinga semiconductor article according to the present invention.

FIG. 12A and FIG. 12B are views illustrating the example of a method ofmanufacturing a semiconductor article according to the presentinvention.

FIG. 13A and FIG. 13B are views illustrating the example of a method ofmanufacturing a semiconductor article according to the presentinvention.

FIG. 14 is a view illustrating the example of the semiconductor articlemanufacturing method according to the present invention.

FIG. 15 is a sectional view of an LED array.

FIG. 16 and FIG. 16A are views illustrating the example of a method ofmanufacturing a semiconductor article according to the presentinvention.

FIG. 17A and FIG. 17B are views illustrating the example of a method ofmanufacturing a semiconductor article according to the presentinvention.

FIG. 18, FIG. 18A, and FIG. 18B are views illustrating the example of amethod of manufacturing a semiconductor article according to the presentinvention.

FIG. 19 and FIG. 19A are views illustrating an example of a method ofmanufacturing a semiconductor article according to the presentinvention.

FIG. 20 is a sectional view illustrating a state where a driver circuitis built directly on the side of an Si substrate and is connected to anLED device.

FIGS. 21A, 21B, 21C, 21D and 21E are views illustrating a process wherea plurality of groups each comprised of a separation layer and alight-emitting layer are laminated on a first substrate.

It is to be noted that a reference numeral 1000 denotes a compoundsemiconductor substrate, a reference numeral 1009 denotes an etchingstop layer, a reference numeral 1010 denotes an etching sacrificiallayer, a reference numeral 1020 denotes a compound semiconductormultilayer film, a reference numeral 1025 denotes a first groove, and areference numeral 2000 denotes, for example, a silicon substrate.Reference numerals 2005, 2006, and 2010 denote a second groove, a thirdgroove, and an insulating film (organic material film), respectively.

BEST MODE FOR CARRYING OUT THE INVENTION First Embodiment

The invention according to the present embodiment is now described withreference to FIGS. 1 to 3.

In FIG. 1, a reference numeral 1000 denotes a first substrate (acompound semiconductor substrate or a substrate formed of, for example,Ge). A reference numeral 1009 denotes an etching stop layer, a referencenumeral 1010 denotes an etching sacrificial layer, and a referencenumeral 1020 denotes a compound semiconductor multilayer film (here,details of the layer structure of the multilayer film are omitted).Further, a reference numeral 1025 denotes a first groove for dividingthe compound semiconductor multilayer film 1020 so as to be in an islandshape on the compound semiconductor substrate. A reference numeral 1009denotes an etching stop layer provided as necessary. A reference numeral100 denotes a member according to the present invention.

Reference numerals 2000, 2005, and 2010 denote a second substrate (forexample, a silicon substrate), a second groove provided in the secondsubstrate, and an insulating film (for example, an organic materialfilm), respectively. The insulating film 2010 is also provided with athird groove 2006 connected to the second groove. Although, in thefigure, the width and spacing of the first groove is shown equal tothose of the second groove, the width of the first groove may be largerthan that of the second groove. However, because it is necessary thatthe first groove 1025 and the semiconductor substrate groove 2005 as thesecond groove are connected to each other, it is desirable that thewidth of an island of the compound semiconductor layer (the length inthe direction of a short side described in the following) is smallerthan the spacing between grooves passing through the second substrate.Although, here, a silicon substrate is used as the second substrate, thesecond substrate is not limited specifically to a silicon substrate.

It is to be noted that, in FIG. 1, the width of the first groove 1025is, for example, from several micrometers to several hundredmicrometers. The width of the second groove 2005 is, for example, fromseveral micrometers to several hundred micrometers. It is to be notedthat, in order that an etchant easily penetrates from the second groove(passing-through groove), the width is preferably 50 μm or more, morepreferably 100 μm or more, and still more preferably 200 μm or more.However, there are cases where the width depends on the thickness of thesecond substrate. It is to be noted that the width of an island of thecompound semiconductor layer is preferably smaller than the spacingbetween grooves passing through the silicon substrate. Further, theinsulating film 2010 may be omitted as appropriated.

FIG. 2 partially illustrates a section 2-2 in FIG. 1. As is clear fromFIG. 2, the compound semiconductor multilayer film 1020 is divided(patterned) in an island shape on the first substrate 1000.

An island portion 1020 is in a projected form compared with portionssurrounding it. Of course, it is enough that the compound semiconductormultilayer film 1020 is patterned in a desired shape, and it is notnecessarily required to be in a rectangular island shape as illustratedin the figure. Further, hereinafter, the direction of a long side of arectangular island is sometimes referred to a longitudinal directionwhile the direction of a short side is sometimes referred to as atraversal direction. It is to be noted that, in FIG. 2, like referencenumerals designate like members in FIG. 1, and the same applies todrawings referred to in the following.

The first groove 1025 is a space (a gap) in the island-shaped compoundsemiconductor multilayer film 1020. It is to be noted that likereference numerals designate like structural members in FIG. 1.

FIG. 3 illustrates a section 3-3 in FIG. 1. As is clear from FIG. 3, thesecond groove 2005 is provided in the second substrate 2000. It is to benoted that the second groove 2005 is intermittently formed. Byintermittently providing the passing-through groove in this way, in thecase of, for example, a silicon wafer, the stiffness thereof is notconsiderably lost, and thus, a situation that handling thereof insubsequent processes becomes difficult can be avoided.

It is to be noted that, as illustrated in FIG. 12B, the passing-throughgroove is preferably formed separately (intermittently) with thelongitudinal direction of the second groove (passing-through groove)being along a chip scribe line which is used when the wafer is separatedinto chips in a downstream process, taking into consideration themechanical strength.

FIG. 4 is a partially exploded perspective view illustrating apositional relationship between the first groove 1025 and asemiconductor substrate groove 2005 and illustrating a state where anisland-shaped compound semiconductor multilayer film 1020 is disposedbetween the semiconductor substrate grooves 2005. It is to be notedthat, in FIG. 4, the insulating film 2010, the etching stop layer 1009,and the etching sacrificial layer 1010 are omitted for the sake ofsimplification.

Further, it is preferable that, when FIG. 2 and FIG. 3 are superposed,an island 1020 a in the projected form is located right betweenpassing-through grooves 2005 a and 2005 b.

Of course, as long as the island 1020 a in the projected form can besupported, the passing-through groove 2005 is not necessarily requiredto be provided so as to be located in parallel with the longitudinaldirection of the patterned compound semiconductor multilayer film 1020as illustrated in FIGS. 2 and 3. For example, (when seen from the top,)the passing-through groove 2005 may be provided so as to beperpendicular to or so as to intersect with the longitudinal direction.It is to be noted that the passing-through groove may also be referredto as a passing-through hole because it passes through the substrate.

The member 100 is prepared which is formed so as to include the firstsubstrate (for example, a compound semiconductor substrate) 1000, theetching sacrificial layer 1010, the compound semiconductor multilayerfilm 1020, the insulating film (for example, an organic insulatingmaterial film) 2010, and the second substrate (for example, a siliconsubstrate) 2000.

The etching stop layer 1009 may be provided as necessary and is notessential.

Then, as illustrated in FIG. 1, an etchant is made to penetrate into themember through the second groove 2005 and the third groove 2006 whichpass through the second substrate 2000 (for example, a siliconsubstrate) and the insulating film 2010, respectively.

By bringing the etchant into contact with the etching sacrificial layer1010, etching is carried out to separate the first substrate 1000 fromthe member.

It is to be noted that, although, in FIG. 1, the first groove 1025passes through the etching sacrificial layer 1010, the first groove 1025is not required to pass through the etching sacrificial layer 1010. Whatis necessary is that the etching sacrificial layer can be exposed whenor before the first substrate 1000 is removed from the member 100.

Further, the etching stop layer 1009 illustrated in FIG. 1 may beprovided as necessary. When the extent of the etching is temporallystrictly controlled, the etching stop layer is not necessarily requiredto be provided. However, this layer has the effect of uniformly exposingthe etching sacrificial layer over the whole wafer.

(Member)

The member may be, for example, prepared according to the following twomethods. Of course, as long as the member illustrated in FIG. 1 can bematerialized, the present invention is not limited to the following twomethods.

A first method is implemented so as to include the following steps A1)to E1):

A1) forming the etching sacrificial layer 1010 on the first substrate1000 such as a compound semiconductor substrate by epitaxial growth;

B1) forming the compound semiconductor multilayer film 1020 on theetching sacrificial layer 1010;

C1) forming the first groove 1025 in the compound semiconductormultilayer film 1020 such that the etching sacrificial layer 1010 isexposed;

D1) preparing the second substrate 2000 which is provided with thesecond groove 2005 and has the insulating film 2010; and

E1) bonding the first substrate 1000 to the second substrate 2000 suchthat the first groove 1025 and the second groove 2005 are connected toeach other.

It is to be noted that, in the step C1 where the compound semiconductormultilayer film is divided in a desired patterned shape, the patterningis carried out such that, for example, as illustrated in FIG. 2, theisland in the projected form remains. It is to be noted that, in C1, atleast part of the surface of the etching sacrificial layer may beexposed, or, the first groove may extend in the direction of the etchingsacrificial layer and the etching sacrificial layer immediately belowthe first groove may be completely removed. Further, regions below theetching sacrificial layer (for example, the first substrate, the etchingstop layer, and/or a buffer layer) may be exposed. It is to be notedthat the third groove may be provided after the step E1 which is abonding process.

Further, as long as the member can be manufactured, the order of theabove steps is not limited to the one specified in the above. Forexample, the step D1) may be carried out before the steps A1) to C1).

Still further, the controllability is further enhanced if the etchingstop layer is epitaxially grown on the compound semiconductor substratebefore the etching sacrificial layer is epitaxially grown. Morespecifically, the uniformity of the etching over the whole substrate isimproved. Although the etching stop layer is formed as shown in FIG. 1,such layer is not essential for the present invention.

Further, preferably, the spacing of the second passing-through grooves2005 formed in the second substrate 2000 such as a silicon substrate andthe width of the compound semiconductor multilayer film separated in anisland shape are substantially equal or the width of the compoundsemiconductor multilayer film is smaller.

Still further, it is to be noted that the second groove 2005 is formedby dry etching (RIE) or the like, for example, halfway in the depthdirection of the second groove illustrated in FIG. 1 (in the figure, thedepth direction is the upward direction), that is, such that thematerial forming the second substrate is partly left on the side of theinsulating film 2010. The mask used in RIE is not specifically limited,and is, for example, SiN. After that, the first substrate 1000 is bondedto the second substrate. Then, the groove formed in the second substratemay be extended in the depth direction by wet etching or the like suchthat the groove passes through the second substrate 2000.

Of course, the second groove 2005 is formed by dry etching (RIE) or thelike, for example, halfway in the depth direction of the second grooveillustrated in FIG. 1 (in the figure, the depth direction is theleftward direction), that is, such that the material forming the secondsubstrate is partly left on the side of the insulating film 2010. Then,after the groove formed in the second substrate is extended by wetetching or the like such that the groove passes through the secondsubstrate 2000, the first substrate 1000 may be bonded to the secondsubstrate.

Although, in the process D1 described in the above, the insulating film2010 is provided on the second substrate, it is also acceptable that,after the insulating film is provided on the compound semiconductormultilayer film 1020 which is patterned in a desired shape, it is bondedto the second substrate. Of course, when the second substrate is asilicon substrate or a substrate having a silicon region, an oxide layerformed on the surface may be used as the insulating film. It is to benoted that the insulating film 2010 disposed in the member 100 may beprovided in advance on the side of the first substrate, on the side ofthe second substrate, or on the side of both the first and the secondsubstrates. It is to be noted that the insulating film 2010 may beomitted when, for example, the second substrate is an insulatingsubstrate such as a quartz and glass substrate.

A second method of preparing the member is carried out according to thefollowing steps:

A2) forming the etching sacrificial layer 1010 on the first substrate1000;

B2) forming the compound semiconductor multilayer film 1020 on theetching sacrificial layer 1010;

C2) preparing the second substrate 2000 which has the insulating film2010;

D2) bonding the first substrate 1000 to the second substrate 2000;

E2) forming the second groove 2005 in the silicon substrate 2000;

F2) forming the third groove 2006 in the insulating film 2010 after thesecond groove 2005 is formed; and

G2) forming the first groove 1025 in the compound semiconductormultilayer film 1020 such that the etching sacrificial layer 1010 isexposed.

It is to be noted that the second groove 2005 is formed by dry etching(RIE) or the like, for example, halfway in the depth direction of thesecond groove illustrated in FIG. 1 (in the figure, the depth directionis the leftward direction), that is, such that the material forming thesecond substrate is partly left on the side of the insulating film 2010.After that, the groove may be made to pass through the second substrate2000 by wet etching.

Although exemplary methods of materializing the member illustrated inFIG. 1 are described in the above, the present invention does notexclude presence of another layer, film, or region between thestructural substrates, structural layers, or structural films, or doesnot exclude film formation or bonding which includes such presence. Forexample, a metal film may be partly or wholly provided between theinsulating film 2010 and the second substrate 2000, and a wiring regionor a circuit region may be provided on the second substrate or may beprovided using the second substrate and the insulating film. The circuitregion referred to herein is a driving circuit or a switching circuitwhen a light-emitting device or a light-receiving device is manufacturedusing the compound semiconductor multilayer film, or a circuit includingwiring just for energization or voltage application.

(Second Substrate)

The second substrate 2000 includes, for example, a semiconductorsubstrate, a silicon substrate, a silicon wafer having an oxide layerformed on the surface thereof, and a silicon wafer having a desiredelectric circuit (for example, a driver) provided thereon. A siliconsubstrate having an insulating film as illustrated in FIG. 1 is formed,for example, as in the following.

After an organic material film as an insulating film is formed on onesurface of the silicon substrate, a mask layer for forming the secondgroove 2005 as a semiconductor substrate groove is formed on the othersurface using a resist, and the semiconductor substrate groove 2005 isformed in the silicon substrate using the mask. Dry etching such as RIEor wet etching may be used. A sandblaster for forming a groove bycausing quartz particles or the like to collide with the exposedportions to physically break the silicon substrate may also be used. Ofcourse, combinations thereof may also be used. For example, a groove maybe formed to some extent in the depth direction by RIE or a sandblaster,and after that, a passing-through hole may be formed in the firstsubstrate formed of silicon or the like by wet etching before (or after)bonding to the first substrate. Alternatively, the groove may also beexposed by grinding or abrasion from the rear surface of the firstsubstrate.

The following is another example. First, the second groove 2005 whichpasses through the silicon substrate is formed. Then, an organicmaterial film (for example, a positive type photosensitive polyimidefilm) is applied on one surface, and UV light is applied from the sideof the other surface with the silicon substrate being the mask. Then,only the portion of the organic material film located above the secondgroove 2005 is developed and removed. Of course, the step of exposingthe organic material film by using the silicon substrate having thepassing-through groove therethrough as the mask and removing the exposedorganic material film may be carried out with the first substrate beingbonded to the silicon substrate. It is to be noted that, after thebonding process, UV light may be applied from the side of the secondsubstrate and the organic material film immediately above the secondgroove may be removed to form the third groove.

Advantages of applying this method in forming the groove in the secondsubstrate are as follows.

Because it is not a device process but a resist shaping for forming thegroove on the silicon substrate, it is a first layer formation whichdoes not require mask alignment. Further, because the size of the grooveis several hundred microns or more, which is relatively large, degassingof the resist is not necessary. Therefore, an inexpensive apparatus withgreat productivity which does not require a pressure reducing mechanismcan be used.

It is to be noted that the method of manufacturing the passing-throughgrooves formed in the silicon substrate and in the insulating film isnot specifically limited, and imprinting using a mold (stamper) having apredetermined pattern may also be used.

It is to be noted that formation of an anisotropic groove in a siliconsubstrate is described in, for example, a document by Ayon, et al.(Sensors and Actuators A91 (2001) 381-385)

This makes it possible to, for example, form a passing-through groove bydeep RIE in a silicon wafer as thick as several hundred microns withside walls being protected and without making worse the aspect ratio.Further, the passing-through groove may be formed not by chemicaletching but by fluid energy or by causing solid particles to collidesuch as sandblasting.

Further, a driver circuit may be provided in the silicon substrate 2000.The driver circuit referred to herein is, for example, a circuit fordriving and controlling the LED, when a light-emitting diode (LED) isformed so as to include the compound semiconductor multilayer film.

It is to be noted that the silicon substrate, a so-called CZ wafer, maybe, of course, a substrate having an epitaxial silicon layer on thesurface thereof. Further, instead of the silicon substrate, an SOIsubstrate may be used.

It is to be noted that, in order that an etchant (for removing theetching sacrificial layer) easily causes penetration through thepassing-through groove of the second substrate such as a siliconsubstrate, the surface of side walls of the passing-through groove inthe silicon substrate may be treated using ozone asking or a piranhasolution which is a mixture of sulfuric acid and hydrogen peroxide.

Further, when the first substrate is bonded to the second substrate suchas a silicon substrate, a metal film may exist therebetween or betweenthe insulating film on the silicon substrate and the first substrate. Itcan function as a reflection layer when an LED device is manufactured.Of course, a DBR mirror may be used instead of the metal film. It is tobe noted that, in order to make the metal film (for example, Ti, Au, orPt) function as a reflective mirror, it may also be provided between theinsulating film and the second substrate (for example, silicon). It isto be noted that when a DBR, that is, a so-called Bragg Reflector isused, the DBR layer is disposed between the compound semiconductormultilayer film 1020 and the insulating film 2010.

As the second substrate, other than the silicon substrate, a glasssubstrate, a quartz substrate, a metal substrate, a ceramic substrate, asubstrate coated with an insulating film, or the like may be applied.Although the thickness of the second substrate is not specified, such athickness as 525 μm (4 inches), 625 μm (6 inches), 725 μm (8 inches), or775 μm (12 inches) may be used. The thickness of the second substrateis, for example, in the range of 300 μm to 1000 μm, and, from theviewpoint of securing the strength and from the process viewpoint,preferably in the range of 400 μm to 800 μm.

It is to be noted that the passing-through groove (passing-through hole)in the second substrate may be a rectangular slit, or may be slits whichare intermittently disposed at specified intervals as illustrated inFIG. 3.

Still further, Die Bonding Film (Hitachi Chemical Co., Ltd.) may be usedto bond the first substrate to the second substrate. For example, theDie Bonding Film manufactured by Hitachi Chemical Co., Ltd. whichfunctions both as a dicing tape and a die bonding film is bonded ontothe second substrate such as a silicon substrate to improve thehandleability. After that, alignment and the like are performed. Inbonding, the dicing tape is removed (for example, removed by UV lightapplication) and bonding to the side of the first substrate isperformed. It is to be noted that, when the die bonding film remains onthe second groove which passes through the second substrate, it isremoved by etching or the like and coupling to the first groove isperformed.

It is to be noted that the passing-through grooves formed in the secondsubstrate are preferably a plurality of passing-through grooves in theshape of rectangles (strips) having a long side and a short side or ofquadrilaterals which are intermittently provided. In particular, it ispreferable that the plurality of passing-through grooves are aligned (inarrays) and intermittently disposed in the direction of the long side(in the longitudinal direction) of the passing-through grooves. Here,“intermittently” means that there is a gap between the grooves, that is,the grooves are separated. This is preferable also from the viewpoint ofsecuring the strength of the substrate which is important when thesubstrate is introduced into a subsequent device process. The width ofthe gap is, for example, in the range of several micrometers to severalhundred micrometers.

Further, it is preferable that the grooves which are intermittentlyprovided in arrays are provided such that the grooves in the arrays arein parallel with one another as illustrated in FIG. 3.

(First Substrate)

As the first substrate 1000, a GaAs substrate, a p-type GaAs substrate,an n-type GaAs substrate, an InP substrate, an SiC substrate, a GaNsubstrate, or the like may be applied. It is to be noted that, otherthan a compound semiconductor substrate, a sapphire substrate or a Gesubstrate may be used. A compound semiconductor substrate such as a GaAssubstrate or a GaN substrate is preferable.

(Etching Sacrificial Layer)

The etching sacrificial layer referred to here is a layer which isetched faster than the compound semiconductor multilayer film, and itcan be also referred to as a separation layer. The etching rate ratio ofthe etching sacrificial layer to the multilayer film thereon is five ormore, preferably ten or more, and more preferably 100 or more.

The etching sacrificial layer is, for example, an AlAs layer or anAlGaAs layer (for example, Al_(0.7)Ga_(0.3)As).

When the AlGaAs layer is expressed as Al_(x)Ga_(x-1)As (1≧x≧0.7), theetching selectivity becomes remarkable when x is 0.7 or more. When anAlAs layer is used as the etching sacrificial layer, a diluted solutionof 2-10% HF may be used as the etchant. The etchant is, for example, 10%hydrofluoric acid.

It is to be noted that a sapphire substrate may be used as the firstsubstrate and a metal nitride film such as chromium nitride (CrN) may beused as the etching sacrificial layer thereon. A multilayer film as afunctional layer for materializing a device (an LED or a laser) for blueor UV light is epitaxially grown on the chromium nitride. With regard tothe multilayer film, GaInN as an active layer and, further, AlGaN or GaNas a spacer layer may be used.

It is to be noted that, as the etchant of the sacrificial layer, acommon Cr etchant (a chromium etchant) may be used. Such an etchant issupplied by Mitsubishi Chemical Corporation.

(Manufacture of Passing-Through Groove in Second Substrate)

When the second substrate is a silicon substrate, the passing-throughgroove may be manufactured by RIE (reactive ion etching) using fluorineunder an atmosphere of SF₆ or the like. Of course, the radical speciesis not limited to fluorine. When wet etching is carried out, NaOH, KOH,TMAH, or the like may be used.

It is to be noted that, in the present invention, as long as the etchantcan be brought into contact with the sacrificial layer under the bondedstate as illustrated in FIG. 1, the etching sacrificial layer may beexposed at any point of time.

The passing-through groove may be formed in the silicon substrate by RIE(reactive ion etching). When wet etching is carried out, a mixture of anoxidant such as HNO₃ and a hydrogen fluoride solution may be used as theetchant using the fact that a silicon oxide is dissolved in hydrofluoricacid. CH₃COOH, Br₂, or the like is used as an additive (MultipleEpitaxial Layer).

The etching sacrificial layer 1010 and the compound semiconductormultilayer film 1020 may be alternately repeatedly laminated on thefirst substrate 1000. In such a case, the compound semiconductormultilayer film can be repeatedly transferred onto the siliconsubstrate. Of course, the etching stop layer 1009, the etchingsacrificial layer 1010, and the compound semiconductor multilayer film1020 may also be alternately repeatedly laminated. Further, thealternate and repeated lamination on the first substrate in advance canavoid a plurality of times of thermal hysteresis for the epitaxialgrowth on the substrate even when the transfer of a pair of asacrificial layer and a multi-layer 1020 is carried out a plurality oftimes one by one, which is preferable. The plurality of times of uses ofthe substrate is expected to have remarkable economic effects, because,generally speaking, a compound semiconductor substrate is ten times ormore as expensive as silicon.

(Compound Semiconductor Multilayer Film)

The layer structure and material of the compound semiconductormultilayer film depend on what device is provided as a semiconductorarticle. Exemplary semiconductor articles as light-emitting devicesinclude a light-emitting diode device (an LED device), a light-emittinglaser diode (an LD device), and a light-receiving device.

For example, when an LED device is provided as a semiconductor article,the layer structure uses the following materials.

A p-AlAs layer (an etching sacrificial layer) is formed on a p-type GaAssubstrate, and the following layers are provided thereon as the compoundsemiconductor multilayer film.

A p-type GaAs contact layer, a p-type AlGaAs clad layer, a p-type AlGaAsactive layer, an n-type AlGaAs clad layer, and an n-type GaAs contactlayer are provided.

It is to be noted that, as the etching stop layer, GaInP may be usedbetween the sacrificial layer and the compound semiconductor substrate.

When the GaAs layer and the AlGaAs layer are etched with sulfuric acid,the etching is stopped by the GaInP layer. After that, the GaInP layeris removed by hydrochloric acid. When the GaAs layer and the AlGaAslayer are etched with ammonia peroxide mixture, AlAs is desirable as thestop layer.

Further, as the material of the compound semiconductor multilayer film,compound semiconductor materials other than GaAs, for example, AlGaInPtype, InGaAsP type, GaN type, AlGaN type, and InAlGaN type can beapplied to the present embodiment.

Further, at least one of a metal film and a DBR mirror may be providedbetween the compound semiconductor multilayer film 1020 and theinsulating film 2010 formed of the organic material or the like.

Here, the metal film is formed of, for example, Au, Ag, Ti, Al, or AlSi,or a multilayer film formed of these materials. A preferable metal filmmaterial is selected according to a wavelength of light to be emitted bythe LED. For example, when a red LED of 700-800 nm is to bemanufactured, Au, Ag, or the like has a high reflectance. In case of ablue LED of about 360 nm, Al is preferable.

A DBR mirror (Bragg Reflector) is formed by, when it is for a GaAscompound semiconductor material, alternately laminating an AlAs layerand an AlGaAs layer a plurality of times or alternately laminating an Aloxide layer and an Al_(0.2)Ga_(0.8)As layer. Because it is difficult toform an aluminum oxide by epitaxial growth, actually, it is preferableto control the index of refraction by, for example, alternatelyswitching the value of x between 0.2 and 0.8 in Al_(x)Ga_(1-x)As. Ofcourse, by making higher the composition ratio of Al in the layer on theside of the lower index of refraction and by its oxidation after thelamination, Al oxide may be formed.

Further, when an LED device is formed using the compound semiconductormultilayer film, instead of a heterojunction LED, a homojunction LED asdescribed in Japanese Patent Laid-Open Application No. 2005-012034 maybe formed. In this case, after forming the respective layers byepitaxial growth, an impurity is diffused by solid phase diffusion toform a pn junction in the active layer.

It is to be noted that, in order that the contact layer forms an ohmiccontact with a p-type electrode or an n-type electrode, an impurityconcentration which is higher than that of the clad layers sandwichingthe active layer is preferable.

It is to be noted that, in FIG. 1, the details of the layer structure ofthe compound semiconductor multilayer film are omitted.

It is preferable that the spacing of patterned island-shaped regions onthe first substrate in the direction of the long side of the rectangularshape (spacing between islands along the direction of the long side)substantially corresponds to the spacing for dicing in a subsequentprocess. It is to be noted that a reference numeral 2901 in FIG. 2denotes the direction of the long side while a reference numeral 2902denotes the direction of the short side.

It is to be noted that, after the etching sacrificial layer is removedfrom the member, further device separation may be carried out such thatdot-like light emitting points are formed in the compound semiconductormultilayer film using a mask or the like.

(Insulating Film)

The insulating film 2010 according to the present embodiment of theinvention is, for example, a film formed of an organic material. A filmformed of an organic material is, for example, a polyimide or otherorganic insulating film, or an insulating film. In this way, a filmformed of an organic material includes an organic insulating film suchas polyimide. More specifically, the insulating film is formed of apositive type photosensitive polyimide. Of course, after the exposure,the exposed portion substantially does not have furtherphotosensitivity. It is to be noted that not only a positive typephotosensitive polyimide but also a negative type photosensitivepolyimide and even a nonphotosensitive polyimide can be applied to thepresent invention as long as a third passing-through groove can beformed using another mask or the like. It is to be noted that such apolyimide is supplied by, for example, HD Micro Systems, Ltd.

Japanese Patent Laid-Open Application No. 2005-012034 describes indetail a photosensitive polyimide. More specifically, an aromaticanhydride reacts with an alcohol having a double bond (for example,hydroxyethyl methacrylate) to form a dicarboxylic acid, which reactswith a diamine to form a polyamide having a double bond on a side chainthereof. This corresponds to a structure where a carboxyl group of apolyamic acid is substituted by a structure having a polymerizabledouble bond. A solution where the polymer is dissolved in a polarsolvent such as NMP (n-methylpyrrolidone) together with aphotoinitiator, a sensitizer, an adhesive aid, and the like is thephotosensitive polyimide.

It is to be noted that a photosensitive or nonphotosensitive polyimidemay be used as the polyimide.

Further, other organic material films can be used for bonding thecompound semiconductor substrate to the silicon substrate. Other thanthe above-described polyimides, an epoxy adhesive layer or the like canbe adopted.

By covering the passing-through groove with the photosensitive organicmaterial film and then applying UV light through the passing-throughgroove, the organic insulating layer above the passing-through groove inthe silicon can be removed in a self-aligning manner.

Further, as the insulating film, not only the organic material filmdescribed in the above but also an inorganic insulating oxide film suchas a silicon oxide film may be used. Further, a siloxane resin or thelike may also be used.

It is to be noted that, when, for example, there is a circuit regionusing the space on and/or inside the silicon substrate as the secondsubstrate, spin on glass (SOG) may be used to form a silicon oxideinsulating film in order to enhance the planarity of the circuit region.Of course, a plurality of kinds of insulating films may be laminated tobe used.

Further, the insulating film may be formed using an organic materialsuch as a polyimide. In particular, carrying out bonding to the firstsubstrate with enhanced adhesion through applying an organic material byspin coating, prebaking to volatilize the solvent, and then enhancingthe adhesion ability is effective from the productivity viewpoint.

Further, in the member illustrated in FIG. 1, the insulating film may beomitted as necessary. Further, the insulating film may be formed of aplurality of layers. An insulating film may be provided on each of theside of the first substrate and the side of the second substrate forbonding, or, the insulating film may be provided on the side of only oneof the substrates.

It is to be noted that, when a driving circuit or the like is providedon or inside the silicon substrate as the second substrate, it ispreferable to provide the insulating film 2010. However, according tothe present invention, the insulating film 2010 may be omitted.

Further, in the present invention, a photosensitive polymer sheet may beused as the insulating film. More preferably, the polymer sheet asitself has adhesion ability. It is to be noted that, when the insulatingfilm is formed on the second substrate or when the insulating film isformed on the side of the first substrate, it may be formed afterheating and pressure-bonding processes. Of course, a dilute organicmaterial (photosensitive polyimide or the like) may be formed into afilm by spin coating. Or, a photosensitive polyimide sheet which is aphotosensitive polyimide formed to be sheet-like such as a dry film maybe used.

(Exemplary Semiconductor Article Manufacturing Method)

An exemplary semiconductor article manufacturing method is described inthe following. More specifically, the method is implemented so as toinclude the following steps:

1) preparing a compound semiconductor substrate (first substrate) and asilicon substrate (second substrate);

2) forming on the compound semiconductor substrate an etching stoplayer, an etching sacrificial layer, a compound semiconductor multilayerfilm including an active layer, and a mirror layer in the stated orderfrom the side of the compound semiconductor substrate (it is to be notedthat the etching stop layer may be used as necessary and is not anessential layer for the present invention);

3) providing a first groove in the compound semiconductor multilayerfilm such that the etching sacrificial layer is exposed to divide thecompound semiconductor multilayer film in an island shape;

4) forming a second groove so as to pass through the silicon substrate;

5) bonding the compound semiconductor substrate to the silicon substrateto form a bonded member such that the second groove provided in thesilicon substrate having an organic material film on the surface thereofand the first groove are connected to each other;

6) bringing the etching sacrificial layer into contact with an etchantthrough the first and second grooves to separate the compoundsemiconductor substrate from the member; and

7) forming an LED device using the compound semiconductor multilayerfilm on the silicon substrate.

The manufacturing method is described in detail in an example describedin the following. It is to be noted that, in the process 2), the presentinvention does not exclude inclusion of a layer other than the describedlayers, and presence of a material other than the layers and filmsdescribed in the above is of course within the scope of the presentinvention.

Further, the member formed by the bonding according to the presentinvention has the following characteristics.

A semiconductor member having a compound semiconductor multilayer filmon a silicon substrate includes an AlAs layer, a compound semiconductormultilayer film, an organic insulating film, and a silicon substrate onthe compound semiconductor substrate in the stated order from the sideof the compound semiconductor substrate, the compound semiconductormultilayer film being provided with a first groove such that thesacrificial layer is exposed, and the silicon substrate and the organicmaterial film being provided with a second groove connected to the firstgroove.

(Others)

It is to be noted that, when the first groove 1020 and the second groove2005 are deep, bubbles of gas (hydrogen) generated by etching theetching sacrificial layer formed of AlAs or the like may block an exitof the grooves. In such a case, it is preferable to continuously orintermittently apply ultrasound (intermittent application is alsoapplicable) to a solution for the etching and to a wafer such as acompound semiconductor substrate. Further, it is also preferable to addalcohol to the etchant (for example, to the hydrofluoric acid).

(Mirror Layer)

At least one of a metal film or a DBR mirror may be provided between thecompound semiconductor light-emitting layer and the insulating film suchas an organic material film. It is to be noted that, when the mirror isa mirror formed of Ti, Au, Pt, AlSi, or the like, the mirror may bebetween the organic material film and the second substrate asillustrated in, for example, FIG. 7. In FIG. 7, a reference numeral 7010denotes an insulating layer and a reference numeral 7081 denotes amirror and the details are described in the following.

Here, the DBR mirror may be continuously epitaxially grown on thecompound semiconductor layer which is epitaxially grown. In such a case,a reference numeral 7021 in FIG. 20 is the mirror layer. The details aredescribed in the following. A metal mirror may be formed by depositionabove the grown compound semiconductor multilayer film, may be formed bydeposition above the organic insulating layer, or the both may besimultaneously formed.

The DBR as the mirror is described in detail in the following.

The DBR layer forms a light-emitting layer which is formed on the firstsubstrate via the etching sacrificial layer (separation layer) so as toinclude the active layer.

Here, the first substrate is a substrate for forming an LED (alight-emitting diode). Here, a substrate on which a compoundsemiconductor film for an LED can be grown is used. Exemplary materialsfor the first substrate include, when an III-V compound which isbasically GaAs is grown, a GaAs substrate and a Ge substrate the latticeconstant of which is close to that of GaAs. In the case of a GaAssubstrate, the substrate may include Al, P, or the like which areelements of the same group. Further, according to the structure of thedevice, an impurity for forming a p-type or an n-type may be included.

The sacrificial layer, the light-emitting layer, and the DBR layer areepitaxially grown on the first substrate in sequence by MOCVD, MBE, orthe like. Here, the sacrificial layer is a layer formed of a materialwhich can be selectively etched in relation to the light-emitting layer,and is formed of, for example, AlAs or Al_(x)Ga_(1-x)As (1≧x≧0.7). Thesacrificial layer of such composition is selectively etched with ahydrofluoric acid solution.

The light-emitting layer is formed of a compound semiconductor layerwhich functions as a light-emitting device, and, for example, GaAs,AlGaAs, InGaAs, GaP, InGaP, AlInGaP, and the like can be used. There isa pn junction in the layer. Further, as a specific structure, thelight-emitting layer 1102 is formed of, for example, an active layersandwiched between clad layers.

The DBR layer can be epitaxially grown on the first substrate, and has astructure where a plurality of pairs each having layers of differentindices of refraction with regard to the target LED wavelength arelaminated.

Each of the pairs is formed of a high refractive index layer and a lowrefractive index layer. That formed by laminating the pair a pluralityof times is referred to as a Bragg reflector film or a DBR mirror (DBRlayer).

The Bragg reflector film obtains a reflectivity which corresponds to thenumber m of the pairs by setting the film thicknesses d1 and d2 of thetwo kinds of films having different indices of refraction such that theoptical film thickness n×d is ¼ of the wavelength and preparing m pairsof the two kinds of films (m is a natural number which is equal to orlarger than two). In that case, the larger the difference between theindices of refraction of the layers forming the Bragg reflector film is,the higher the obtained reflectivity is, even if the number of the pairsis small. It is to be noted that, in the present invention, it ispreferable that the conditions for forming the DBR are optimized suchthat a light of a specific wavelength can be reflected with theefficiency of 70% or more, preferably 80% or more, and more preferably90% or more.

For example, the DBR layer is obtained by alternately laminating AlGaAslayers containing different amount of Al. Here, when the etchingsacrificial layer is selectively removed, in order to suppress damage tothe DBR layer, it is preferable that the amount x of Al which iscontained in the layer is 0.8 or less when the material is expressed asAl_(x)Ga_(1-x)As. The amount x is preferably 0.7 or less, morepreferably 0.6 or less, and still more preferably 0.4 or less. The lowerlimit of x is, for example, zero.

In any case, the low refractive index layer which forms the DBR layerand the index of refraction of which is lower than the other layer isselected from the group consisting of Al_(x)Ga_(1-x)As (0≦x≦0.8), anAlInGaP type material, and an AlGaP type material. It is important thatthe etching sacrificial layer is selected from the group consisting ofAlAs and Al_(x)Ga_(1-x)As (0.7≦x≦1.0) and the combination of thematerials is such that the low refractive index layer is resistant todamage when the separation layer is selectively etched and removed. Itis to be noted that, when an AlAs layer is selected as the sacrificiallayer and an AlInGaP type material or an AlGaP type material is used asthe low refractive index layer, the separation layer may be selectivelyremoved without greatly depending on the amount of Al contained.

It is to be noted that, with regard to the structure of the DBR layer,the following three examples of combination of (high refractive indexlayer/low refractive index layer) are listed as DBR structures havinghigh resistance to hydrofluoric acid:

1) Al_(0.6)Ga_(0.4)As/Al_(0.2)Ga_(0.8)As

2) AlInGaP/Al_(0.2)Ga_(0.8)As

3) AlGaP/Al_(0.2)Ga_(0.8)As

It is to be noted that, when a laser (LD) is manufactured, because areflectivity of 99.9% or more is required, it is necessary to form 30layers, 40 layers, or more of the pair. However, in the case of an LEDwhere a reflectivity of 90% or more is satisfactory, several layers toabout ten layers are satisfactory.

For example, a p-AlAs layer as a separation layer of a thickness of 100nm, a light-emitting layer of a thickness of about 2000 nm, and an n-DBRlayer are grown on a 4-inch GaAs substrate 100 by MOCVD. The details ofthe light-emitting layer are as follows. It is formed ofp-Al_(0.4)Ga_(0.6)As: 350 nm as a clad layer, p-Al_(0.13)Ga_(0.87)As:300 nm as an active layer, and n-Al_(0.23)Ga_(0.77)As: 1300 nm to be aclad located on the side of the DBR layer. With regard to the details ofthe n-DBR layer, it can be formed by laminating 20 pairs ofAl_(0.2)Ga_(0.8)As: 633 Å/Al_(0.8)Ga_(0.2)As: 565 Å. It is to be notedthat, by making lower the resistivity of the materials forming the DBR,electrical connection can be secured from the DBR mirror denoted as 7021in FIG. 20.

Of course, a structure where the DBR is provided on both sides of theactive layer is also possible. As described in the following, when a rodlens array is omitted in a printer head, this structure is preferablethough not essential.

(Etching Stop Layer)

When an AlAs layer is used as the etching sacrificial layer, which isnot necessarily required in the present invention, GaInP, for example,can be used as an etching stop layer.

(Buffer Layer)

It is to be noted that, by forming a buffer layer before the etchingsacrificial layer is grown on the first substrate, for example, acompound semiconductor substrate such as a GaAs substrate, a Gesubstrate, or a GaN substrate, a satisfactory epitaxial layer with asmall number of defects can be obtained. For example, a GaAs thin filmas the buffer layer can be formed on the GaAs substrate. In the case ofa Ge substrate, GaInAs or the like is suitable for lattice strainrelaxation.

(Alignment)

It is to be noted that the alignment between the first substrate and thesecond substrate can be performed using a double-sided aligner used forwafer bonding or the like. In particular, when the second substrate is asilicon substrate, the passing-through groove provided in the substratemay be used as an alignment mark. Further, the passing-through groovemay be formed on a scribe line. The light-emitting layer transferredonto the silicon has an area as large as several hundred microns whichcorresponds to a chip size, and device separation of individuallight-emitting devices of several ten microns and the like are fixed ina process after the transfer. Therefore, bonding the island-shapedactive layer to the passing-through groove does not require the accuracyof several microns which is required in a device process, and anaccuracy of several ten microns is satisfactory. From this viewpoint, anorientation flat of a wafer may be used as the standard of thealignment.

(Bonding and Separating Processes)

Description with regard to the bonding is now made. The bonding iseasily carried out by heating to a temperature of several hundreddegrees or higher which is the glass transition temperature of theorganic insulating layer as the insulating film 2010 in FIG. 1 to givetackiness thereto and by press bonding the silicon wafer. The bondingstrength is satisfactory with no problem in subsequent processes. A voidwhich is liable to occur in direct bonding without using an adhesivelayer and without tackiness is separated in an island shape and theactive layer exists. Therefore, intake of air easily disappears alongthe separation groove between the islands in pressure bonding. Bondingunder a reduced pressure decreases the amount of the void itself, andthus, formation of the gap itself is drastically reduced. In order totransfer and separate two wafers bonded to each other, an etchant bathmay be disposed in a vacuum to soak the member in the etchant under areduced pressure such that the etchant penetrates into the sacrificiallayer more uniformly through the passing-through groove. Further,vibration by ultrasound, heating, and rotational motion such as axialrevolution and orbital revolution of the wafer itself increase liquidcirculation speed to complete the transfer and separating processesuniformly in a short time.

It is to be noted that, in the following, a method of forming a compoundsemiconductor multilayer film on a first substrate such as GaAs via anetching sacrificial layer (also referred to as a separation layer) andforming a pair formed of the two layers a plurality of times such thatdecreasing the cost of the process can be expected is described.

(About Multiple Epitaxial Growth)

Description is made with reference to FIGS. 21A to 21E.

In FIG. 21A, a reference numeral 1000 denotes a first substrate (forexample, GaAs), and a reference numeral 2101 denotes a buffer layer.

Because AlAs (AlGaAs) having highly selective etching characteristics isused as a separation layer 2102, a substrate on which such layers can beepitaxially grown is the first substrate. Exemplary substrates include aGaAs substrate and a Ge substrate the crystal lattice constants of whichare close to that of AlAs (AlGaAs). Although the lattice constant of Siis different from that of GaAs by about 4%, it is possible to directlygrow GaAs on Si. Therefore, it is also possible to use an Si substratehaving a GaAs film grown thereon as the first substrate 1000. Further,an impurity may be doped in these substrates.

Portions other than the first substrate 1000 in FIG. 21A are nowdescribed.

The separation layer 2102 and a light-emitting layer 2103 including anactive layer are epitaxially grown on the first substrate 1000 insequence.

The material of the separation layer 2102 is AlAs orAl_((x))Ga_((1-x))As (x≧0.7), and the film thickness is preferablyseveral ten to several hundred nanometers.

The light-emitting layer 2103 is a compound semiconductor multilayerfilm as a light-emitting device, and, for example, GaAs, AlGaAs, InGaAs,GaP, InGaP, or AlInGaP is used. There is a pn junction in thelight-emitting layer 2103.

It is to be noted that, although there is a case where a buffer layer2101 is formed prior to formation of the separation layer 2102, this isarbitrary. The object of the buffer layer 2101 is to decrease crystaldefects and the like.

As long as the growth can be uniform, the growth method is notspecifically limited, and any of MOCVD, MBE, LPE, and the like may beused.

Further, the separation layer 2102 and the light-emitting layer 2103 arepaired, and a plurality of pairs of separation layers 3102 and 4102 andlight-emitting layers 3103 and 4103 are grown in sequence such that thenumber of the pairs reaches n. Here, it is not necessary to make uniformthe thickness of the separation layer 2102. It is also possible to makethe thickness smaller as the layer goes up.

This is one method to avoid useless etching as much as possible in alower layer portion of an outer peripheral portion of the firstsubstrate 1000 taking into consideration such a characteristic that,when the separation layer 2102 is side-etched, the smaller the filmthickness is, the higher the etching rate is.

Then, as illustrated in FIG. 21B, a light reflection layer 4104 isformed on the uppermost light-emitting layer 4103.

Then, a resist patterning 2105 is formed so as to leave the lightreflection layer 4104 in an island shape.

The material of the light reflection layer 4104 is preferably a materialhaving a high reflectivity with respect to the wavelength of alight-emitting device to be formed. For example, when the material ofthe light-emitting device is of the GaAs type and the light-emittingwavelength is about 750-800 nm, Au (gold), Ag (silver), Al (aluminum),and the like are preferable. Of course, other light-reflecting materialsmay be used.

In the case of a blue light-emitting device the wavelength of lightemitted by which is about 360 nm, the material of the light reflectionlayer 4104 is preferably Al or the like. It is to be noted that the DBRlayer described in the above may be used instead of the light reflectionlayer, and it may be possible that no specific light reflection layer isprovided. In other words, the light reflection layer 4104 may beomitted.

Further, the light-emitting layer 4103 in an island shape may form alight-emitting layer of one light-emitting device or may be a regionwhere a plurality of light-emitting devices are included in an array.Here, it is preferable that the size of the island-shaped light-emittinglayer 4103 is in agreement with the chip size when the second substrate2000 to be described below is diced.

The light reflection layer 4104 is not essential. It may be formed onthe side of the second substrate 2000 described in the following, or itmay be completely omitted.

Then, as illustrated in FIG. 21C, the light reflection layer 4104 andthe uppermost light-emitting layer 4103 are etched in an island shape toexpose part of the uppermost separation layer 2102. It is to be notedthat the above-described first groove surrounds the light-emitting layersuch that the light-emitting layer is in an island shape.

As illustrated in FIG. 21D, the first substrate 1000 is bonded to thesecond substrate 2000.

The material of the second substrate 2000 is arbitrary, and any materialmay be used including a semiconductor substrate such as an Si substrate,a conductive substrate, and an insulating substrate. As described in theabove, a driver circuit for driving the light-emitting layer and thelike may be provided. Further, an insulating film such as an organicmaterial film may be provided on the surface.

Further, a light reflection layer 4104 may be formed on the surface ofthe second substrate 2000. Further, the reflection layer 4104 may beformed on the surfaces of the first substrate 1000 and of the secondsubstrate 2000 or the reflection layers 4104 may be bonded to eachother.

As the method of bonding the first substrate 1000 to the secondsubstrate 2000, heating after bonding, pressurizing, using the both, andthe like may be used. Bonding in an atmosphere under a reduced pressureis also effective.

It is to be noted that, as already described, although the second groove(passing-through groove) according to the present embodiment is providedin the second substrate 2000, it is omitted in the drawings.

As a result of the bonding, space 2106 made by the patterned groove isformed in proximity to the interface. The first groove and the secondgroove are connected to the space 2106.

FIG. 21E is a view illustrating a state where the substrates areseparated.

The separation is achieved by etching the separation layer 4102 which isthe uppermost layer.

Here, the etchant flows into the space 2106 formed by the island-shapedseparation region.

The separation layer 4102 which is the uppermost layer is etched, and,as a result, the first substrate 1000 and the second substrate 2000 areseparated. As the etchant used here, a hydrofluoric acid solution, ahydrochloric acid solution, or the like may be used.

As a result, the light-emitting layer 4103 in the island-shaped regionis transferred onto the second substrate 2000.

The second substrate 2000 onto which the light-emitting layer 4103 istransferred proceeds to the device process, and a light-emitting deviceis formed.

On the other hand, the surface of the first substrate 1000 which lostthe uppermost light-emitting layer 4103 and the uppermost separationlayer 4102 due to the transfer and etching becomes the light-emittinglayer 4103, and the process returns to the one illustrated in FIG. 21A.

When the light-emitting layer 4103 and the separation layer 4102 arepaired, by repeating n times the above-described process in which n isthe number of times the pair is formed, substrates for forming nlight-emitting devices can be formed. It is to be noted that, although acase where the separation layer and the light-emitting layer are pairedis described, the reflection layer may be added to the pair to form aset of the three layers and the set may be laminated a plurality oftimes.

As described in the above, according to the present invention, a novelsemiconductor article manufacturing method and a novel member areprovided. When a light-emitting device, typically an LED, ismanufactured in a chip, further, a device separating process, a wiringprocess, a process for dicing the second substrate, and the like areappropriately performed. With regard to the device separation formanufacturing an LED having a plurality of light emitting points on achip, for example, when the conductivity type of the front surface sideof the compound semiconductor multilayer film is p, patterning iscarried out to an n-type layer below that or nearly to the active layerto remove them. In this way, the device separation can be carried out.It is to be noted that the direction of the dicing and the secondpassing-through groove may be opposite to those in the case illustratedin FIG. 3. More specifically, not the passing-through groove along thedirection of the long side of the chip as illustrated in FIG. 3 but apassing-through groove perpendicular thereto is provided along thedirection of the short side. In such a case, when the arrangement is inan array along the direction of the long side of the rectangle of theupper surface, the space between chips has a side surface formed not bydicing but by a passing-through groove (manufactured by, for example,RIE) provided in advance. This is preferable taking into consideration acase where dense arrangement is made. Of course, it is also preferableto form grooves intermittently provided along both the direction of thelong side and the direction of the short side of the chip. In such acase, a passing-through groove along the direction of the long side anda passing-through groove along the direction of the short side areintermittently provided below the island-shaped compound semiconductormultilayer film.

Second Embodiment

By using the manufacturing method described in the first embodiment, anLED array as illustrated in FIG. 6 is provided. FIG. 6 is a sectionalview illustrating an exemplary structure where a driving circuit and anLED array are connected on a wiring substrate. The LED array can beobtained by, in the process (7) of the above-described semiconductorarticle manufacturing method, forming a plurality of LED devices on anisland-shaped compound semiconductor multilayer film on a siliconsubstrate and dividing the silicon substrate by dicing. The crosssectional structure of the respective LED devices is the same as LEDdevices including an LED light emitting region on the left in FIG. 7 andFIG. 15 described in the following. In FIG. 6, a plurality of LED arraychips 4000 are arranged on a wiring substrate 5000 in a line, and aplurality of driver ICs 3050 similarly arranged in a line on both sidesof the plurality of LED array chips 4000, and the LED array 4000 areelectrically connected with the plurality of driver ICs 3050 by wirebonding. The respective LED devices of the LED array chips 4000 areelectrically connected with drive devices of the driver ICs 3050alternately arranged on both sides of the LED array chips 4000 by wirebonding. Here, the plurality of driver ICs 3050 are arranged in a lineon both sides of the plurality of LED array chips 4000 disposed in aline. Of course, if mounting is possible, the plurality of driver ICs3050 may be arranged on one side of the plurality of LED array chips4000.

Further, by mounting, as necessary, a rod lens array (for example, anSLA: Selfoc Lens Array) 3000 on the LED array chips 4000 arranged in aline, an LED printer head (FIG. 5) may be formed. Light emitted from theLED array 4000 disposed in a line is collected by the rod lens array3000 to obtain an LED array image 3060.

It is to be noted that, when, as described in the above, an LED deviceforming layer is provided on the silicon substrate via a metal film or aDBR mirror, by improving the directivity and increasing the brightness,a device light emitting point having enough brightness is materializedeven if the device dimension is one obtained by microfabrication.Therefore, it is possible to omit the rod lens array and to directlyform a latent image on a photosensitive member directly from an LEDprinthead, and the LED printer head having the structure illustrated inFIG. 5 the number of parts of which is small and the economic effect ofwhich is great may be formed.

It is to be noted that, although FIG. 6 illustrates a case where thedriver ICs (driving circuit) and the LED devices are connected with eachother by wire bonding, the driver circuit may be directly built on theside of the Si substrate to be connected with the LED devices (FIG. 7 inwhich a reflection layer is provided on an organic insulating layerimmediately below a device).

In FIG. 7, an insulating film 7010 formed of an organic material isprovided on a silicon substrate 7000 including a MOS transistor 7060which forms a driver IC. Then, an LED light emitting region 7070 formedof a compound semiconductor multilayer film is provided on theinsulating film 7010. A reference numeral 7080 denotes an insulatingfilm (such as SiO₂ or SiN) and a reference numeral 7050 denotes a wirepad to be a source or drain region of the MOS transistor 7060. Areference numeral 7081 denotes a layer which functions as a mirror (forexample, a metal mirror of Ti, Au, or the like) and reference numerals7083 and 7084 denote wiring, embedded wiring, or an electrode pad.

In this way, by including the driver ICs for driving on the side of thesecond substrate to be bonded, as illustrated in FIG. 19, a chip 1960illustrated in FIG. 19 can be cut out by dicing in a dicing direction1625. It is to be noted that FIG. 19 illustrates a state where the cutchip arrays 1960, an enlarged view of which is shown in FIG. 19A, arearranged on a print substrate 1930. A reference numeral 1911 denotes asecond substrate. It is to be noted that, although a second groove whichis a passing-through groove is intermittently provided in the secondsubstrate along the long side of the chip as illustrated in FIG. 3, itis omitted in FIG. 19.

It is to be noted that FIG. 8 illustrates an exemplary matrix drive.FIG. 8 is a view illustrating a light-emitting device array circuit 8500which can be time-division driven for decreasing the number ofelectrodes. In FIG. 8, a reference numeral 8011 denotes an n-sideelectrode, a reference numeral 8017 denotes a p-type electrode, areference numeral 8021 denotes an insulating film on n-type AlGaAs, areference numeral 8022 denotes an insulating film on a p-type GaAscontact layer, and a reference numeral 8023 denotes a light emittingregion.

It is to be noted that, although, in the present embodiment, the LEDarray chip using an LED as a light-emitting device is used, of course,an LD (Laser Diode) array chip may be used.

FIG. 20 illustrates an exemplary modification of an embodimentillustrated in FIG. 7. Like reference numerals are used to designateportions having functions like ones in FIG. 7. In FIG. 7, the mirror7081 is provided on the side of the organic insulating film 7010 and thesilicon substrate 7000. In FIG. 20, a mirror layer 7021 (a metal mirror,a DBR layer, or the like) is provided directly on the compoundsemiconductor multilayer film 1020. In such a case, because lightgenerated by the light emitting region 1020 toward the substrate can bereflected without passing through the organic insulating film 7010, theperformance is extremely increased. In FIG. 7, electrical connectionwith the driving circuit 7060 is made using the mirror layer 7021. It isto be noted that, when the mirror layer is a low resistance (n+) DBR,similarly, the mirror can be used to make electrical connection with thedriving circuit.

Third Embodiment

FIG. 9A illustrates an exemplary structure of an LED printer using theLED printer head described in the second embodiment.

FIG. 9A is a schematic sectional view illustrating an exemplarystructure of the LED printer according to the present invention.

In FIG. 9A, a photosensitive drum 8106 which rotates clockwise is housedin a printer body 8100. An LED printer head 8104 for exposing thephotosensitive drum is provided above the photosensitive drum 8106. TheLED printer head 8104 is formed of an LED array 8105 where a pluralityof light-emitting diodes which emit light according to an image signaland a rod lens array 8101 for imaging the light emitting pattern of therespective light-emitting diodes on the photosensitive drum 8106. Here,the rod lens array 8101 has the structure described in the aboveembodiment. The arrangement is made such that the imaging surface of thelight-emitting diodes produced by the rod lens array 8101 and thelocation of the photosensitive drum 8106 are aligned with each other.More specifically, the light emitting surface of the light-emittingdiodes and the photosensitive surface of the photosensitive drum aremade to be in an optically conjugate relationship by the rod lens array.

A charging unit 8103 for uniformly charging the surface of thephotosensitive drum 8106 and a developing unit 8102 for making tonerattach to the photosensitive drum 8106 according to an exposure patternby the printer head 8104 to form a toner image are provided around thephotosensitive drum 8106. A transfer charging unit 8107 for transferringa toner image formed on the photosensitive drum 8106 onto a transfermaterial such as a copy sheet, not shown in the figure, and cleaningmeans 8108 for collecting residual toner on the photosensitive drum 8106after the transfer are provided around the photosensitive drum 8106. Inthis way, an imaging unit is formed.

Further, a sheet cassette 8109 loaded with the transfer material andsheet feeding means 8110 for supplying the transfer material in thesheet cassette 8109 between the photosensitive drum 8106 and thetransfer charging unit 8107 are provided in the printer body 8100.Further, a fixing device 8112 for fixing the transferred toner image onthe transfer material, transport means 8111 for leading the transfermaterial to the fixing device 8112, and a sheet discharge tray 8113 forholding the transfer material discharged after the fixing are provided.

FIG. 9B is a schematic view illustrating the structure of an exemplarystructure of a color printer according to the present invention. Thereare a plurality of (four in the figure) imaging units. In FIG. 9B,reference numerals 9001, 9002, 9003, and 9004 denote magenta (M), cyan(C), yellow (Y), and black (K) photosensitive drums, respectively,reference numerals 9005, 9006, 9007, and 9008 represent LED printerheads. A reference numeral 9009 denotes a conveyor belt for transportingthe transferred sheet and for making contact with the respectivephotosensitive drums 9001, 9002, 9003, and 9004. A reference numeral9010 denotes a resist roller for sheet feeding, and a reference numeral9011 denotes a fixing roller. A reference numeral 9012 denotes a chargerfor sucking and holding the transferred sheet onto the conveyor belt9009, a reference numeral 9013 denotes a charge eliminating charger, anda reference numeral 9014 denotes a sensor for detecting a leading edgeof the transferred sheet.

Fourth Embodiment

It is to be noted that, using the semiconductor article manufacturingmethod described in the first embodiment, an LED device can bemanufactured, and, using the LED device, a display device such as adisplay can be manufactured. In such a case, it is preferable to prepareLEDs which have a plurality of wavelengths.

Fifth Embodiment Bonded Structure

The invention according to the present embodiment relates to a bondedstructure formed by bonding a first substrate to a second substrate.

Regions (1020 in FIG. 2) including a compound semiconductor multilayerfilm patterned in an island shape are provided on the first substratevia a separation layer, and there is a first groove (1025 in FIG. 1)between the compound semiconductor multilayer film regions.

The shape of the compound semiconductor multilayer film regions seenfrom the top is a rectangle having a long side direction 2901 and ashort side direction 2902.

The second groove 2005 which passes through the second substrate isprovided in the second substrate 2000. By intermittently providing aplurality of the second grooves in parallel along the direction of thelong side, a passing-through groove group in the direction of the longside (3998 in FIG. 3) is formed.

The passing-through groove group in the direction of the long side 3998is characterized in that a plurality of the passing-through groovegroups are arranged so as to be in parallel with one another atintervals which are equal to or longer than the length of the short sideof the island-shaped compound semiconductor multilayer film regions. Theintervals referred to here are denoted by arrows 3999 in FIG. 3. In astate where the two substrates are bonded to each other, the region 1020is located between two second grooves. With this state, by dicing thebonded structure in the direction of the short side, chips can beformed.

It is to be noted that the separation layer, the first and secondsubstrates, the region including the compound semiconductor multilayerfilm and the like which appear in the description of the presentembodiment are all applied except in cases where the description in theabove-described embodiments becomes inconsistent. In particular, it isalso preferable that, with regard to the second substrate, the siliconwafer is provided with a driver such as a driving circuit.

It is to be noted that the length in the direction of the long side ofthe region 1020 may be equal to or shorter than the length of the secondpassing-through groove in the direction of the long side. Of course, forexample, the length of the region 1020 in the direction of the long sidemay be set to the length corresponding to that for four passing-throughgrooves.

Sixth Embodiment

Further, another aspect of the present invention has the followingcharacteristics.

A method of manufacturing a light-emitting device including forming on afirst substrate a separation layer and a light-emitting layer in thestated order from the side of the first substrate, forming a bondedmember by bonding the first substrate to a second substrate with thelight-emitting layer being positioned inside, and transferring thelight-emitting layer onto the second substrate by etching and removingthe separation layer, characterized in that, with the separation layerand the light-emitting layer on the first substrate being regarded asone pair, formation of the pair is repeated n times (n is a naturalnumber which is equal to or larger than two), after patterning only theuppermost light-emitting layer in the shape of a plurality of islands,the first substrate is bonded to the second substrate to form a bondedstructure, and an etchant is caused to penetrate into a space formed inthe bonded structure by the island-shape patterning to bring theseparation layer into contact with the etchant to selectively transferthe island-shaped light-emitting layer onto the second substrate.

Seventh Embodiment

Further, still another aspect of the present invention has the followingcharacteristics.

A light-emitting device characterized in that a light-emitting device isprovided on a silicon substrate via a DBR mirror.

After a so-called microcavity LED structure with a DBR is formed, thestructure is transferred onto a silicon substrate to materialize a spotwith higher directivity, and a contact-type printer head where a rodlens is not essential can be obtained.

Further, an LED array manufacturing method includes forming a separationlayer, a light-emitting layer, and a DBR layer in the stated order onthe surface of a first semiconductor substrate and bonding it to asecond substrate having a semiconductor circuit formed thereon via aninsulating film, transferring the light-emitting layer and the DBR layerof the first substrate onto the second substrate by etching and removingthe separation layer, making the transferred light-emitting layer in anarray of a plurality of light-emitting portions, and electricallyconnecting the plurality of light-emitting portions with an electrodeportion of the semiconductor circuit for controlling light emission ofthe light-emitting portions.

The present invention is described using an example in the following.

Example

An example is described with reference to FIGS. 10 to 18B.

First, a p-GaAs substrate 1000 is prepared. After a buffer layer whichis not shown in the figures is formed as necessary, a GaInP layer as anetching stop layer 1009 is formed. A p-AlAs layer as an etchingsacrificial layer 1010 is formed on that. Further, a compoundsemiconductor multilayer film 1020 is formed. The multilayer film isformed of an n-type GaAs contact layer, an n-type clad layer, a p-typeactive layer, a p-type clad layer, and a p-type contact layer from thetop in the stated order.

Further, on that, an AlGaAs multilayer film (ten pairs ofAl_(0.8)GaAs/Al_(0.2)GaA) 1022 is formed to function as a DBR mirror(FIG. 10).

It is to be noted that the etching stop layer, the sacrificial layer,and the compound semiconductor multilayer film may be repeatedly formed(multiple epitaxial growth). An example of such case is illustrated inFIG. 11. A GaInP layer as an etching stop layer 1109 is formed on theAlGaAs multilayer film 1022. A p-AlAs layer as an etching sacrificiallayer 1110 is formed on that. Further, a compound semiconductormultilayer film 1120 is formed. Further, on that, an AlGaAs multilayerfilm (ten pairs of Al_(0.8)GaAs/Al_(0.2)GaA) 1022 is formed to functionas a DBR mirror.

As illustrated in FIG. 11, a first groove 1125 is formed by etching witha resist being as a mask. The epitaxial layer 1120 is separated intochips. For example, a size of 250 μm×8 mm and a separation width ofabout 80 μm which correspond to a scribe line are preferable.Alternatively, for the purpose of promoting the etching, the chip widthof 250 μm may be decreased. The shortest possible length may be severalten microns which is the size of the individual LED device.

As illustrated in FIGS. 12A and 12B, a passing-through groove(semiconductor substrate groove) 2005 is formed like a scribe line inthe silicon substrate 2000. The groove is in the shape of a rectangle of80 μm×8 mm and is formed in the silicon substrate so as to pass throughthe wafer in the longitudinal direction along the scribe line. As themethod, deep RIE which is practically used in MEMS, sandblasting, or thelike is applied. It is to be noted that the silicon substrate having thegroove formed therein may have a driving circuit formed thereon, or maybe used as it is with no device layer, using such originalcharacteristics of silicon that the thermal conductivity is three timesas high while the price is less than one tenth.

Then, a positive type photosensitive organic insulating film polyimideis spin coated to cover the passing-through groove with thephotosensitive organic insulating film (organic material film) 2010.After that, UV light is applied through the passing-through groove. Thismakes it possible to remove the organic insulating film above thepassing-through groove in the silicon in a self-aligning manner. In thisway, a third passing-through groove 2006 is provided in the organicinsulating film. The positive type photosensitive polyimide and theorganic insulating layer used as a permanent adhesive layer are appliedon the surface of the silicon substrate with the groove, and thepolyimide covering the groove is exposed and developed by the UV lightapplication from the rear surface of the substrate and is removed.

FIG. 12B illustrates the passing-through groove seen from the top of afour- or six-inch wafer.

As illustrated in FIGS. 13A and 13B, the two substrates are bonded toeach other. The bonding is carried out by pressurization and heatingafter preheating the organic insulating film 2010 to a temperaturehigher than the glass transition temperature to enhance the adhesion. Itis to be noted that, when multiple transfer is carried out using amultiple epitaxial layer, after the DBR reflection layer and the devicelayer are etched to the AlAs sacrificial layer with regard to each chipsize, the bonding is carried out in order to cause an etchant topenetrate into the groove. It is effective to cause an etchant to entertherein or to help the entry of an etchant using a jet stream. It isalso effective to put the bonded wafer pair under a reduced pressure orto decompress the gap to promote the entry of the etchant.

The surface of the epitaxial layer separated by the groove existing inthe organic insulating film is pressed against, adhered to, and bondedto the surface of a tacky (adhesive) polyimide to materialize bondingwithout a void. The polyimide layer is used as an adhesive layer and asa permanent insulating layer for device separation. It is preferablethat a metal mirror or a DBR mirror is directly provided on the side ofthe bonded epitaxial layer as a light reflection layer. In that case,compared with a case where a reflector layer is embedded below theorganic insulating film, light loss due to light absorption is avoided,and light is amplified by double, or, when taking into consideration thewhole reflectivity of the interface, further light amplification ispossible.

Next, the bonded member is soaked in a diluted solution of 2-10% HF toselectively etch and remove the AlAs sacrificial layer 1110. By soakingthe bonded substrate in the diluted solution of HF, selective etching ofabout a hundred thousand times selectivity dissolves the separationlayer provided on the interface between the epitaxial layer and the GaAssubstrate, and the separation is completed in a short time. When thereis no island-shaped separation, depending on the size of the wafer, itmay take one week or more to separate the whole area of the wafer.

It is to be noted that, when it is difficult for the etchant topenetrate, it is effective to apply ultrasound or pressure to theetchant to cause the etchant to enter therein, or to help the entry ofthe etchant using a jet stream. It is also effective to put the bondedwafer pair under a reduced pressure or to decompress the gap thereby topromote the entry of the etchant.

Then, as illustrated in FIG. 14, the GaAs substrate 1000 separates fromthe member.

After that, the n-layer of the epitaxial layer is exposed by mesaetching. More specifically, as illustrated in FIG. 15, by doping ann-type impurity into a contact layer where a cathode electrode is formedbelow a clad layer or a reflection DBR mirror, a low resistance layer isformed. Then, an etching stop layer which is GaInP or the like isprovided immediately above it, and, as illustrated in the figure, thesection of the LED is shaped so as to be trapezoidal and the cathodecontact layer is exposed by mesa etching. After that, a passivation filmis formed, a contact hole is formed, and the contact hole is filled witha metal to form an LED device.

A reference numeral 9000 denotes a silicon substrate. A driver circuitmay be formed thereon as necessary. A reference numeral 9010 denotes aninsulating film which is, for example, an organic material. A referencenumeral 9015 denotes a wire bonding pad. An insulating film 9010 may beprovided as necessary. A reference numeral 9040 denotes a portion whichfunctions as a mirror formed of a metal or the like. This layer may alsobe provided as necessary. A reference numeral 9050 denotes wiring. Areference numeral 9030 denotes an epitaxial layer, and has, for example,a multilayer structure. A reference numeral 9020 denotes an insulatingfilm. The epitaxial layer 9030 is mesa etched or is subject to deviceseparation as necessary for point emission. This separation (into anarray) can be carried out with regard to the respective light emittingpoint by carrying out the removal until the active layer is exposed oruntil the n-type layer is exposed, if the conductivity type (p or n) ofthe surface is, for example, p-type, when the multi-layer structure isseen from the top.

A reference numeral 9041 denotes a portion provided as necessary, andis, for example, a low resistance layer continuously formed on themultilayer film 9030. In other words, the portion 9041 may be omitted.It is to be noted that, when the portion 9040 is a metal, electricalconnection with the draw out wiring 9015 is avoided. However, the drawout wiring 9015 and the portion 9040 may be electrically connected suchthat potential equal to that of the wiring 9015 is maintained.

By conducting sawing in a traversal direction of a chip 1600 along adirection 1625 of operating a dicing saw as illustrated in FIG. 16, thewafer is cut, and end portions of the passing-through grooves 2005aligned in the longitudinal direction of the chips are connected by thesawing. In this way, individual chips 1600 are separated. Of course, bybonding the wafer to a dicing tape, scattering can be prevented in thechip separation. It is to be noted that, in FIG. 16, a reference numeral1611 denotes a second substrate (for example, a silicon wafer), andreference numerals 1605 and 1705 denote second passing-through groovesprovided in the second substrate. Small rectangles in the chip 1600schematically illustrates light emitting regions.

It is to be noted that, when chipping on end surfaces is a problem inmaterializing a long array by connecting end surfaces of high densitychips, a separation groove is formed between the chips in a directionperpendicular to the longitudinal direction of the chips and a dicingsaw is operated in the longitudinal direction. Primarily, cutting of asilicon substrate generates less chipping than cutting of a fragilecompound semiconductor substrate. In particular, in the case of 2400 DPIwhere the distance between devices is about 10 μm and chips have to beconnected with such precision, smoothness of groove end surfaces shapedby RIE is effective. It is also effective to leave silicon on four sidesof chips and form a passing-through groove therearound. In that case,chip separation is possible only by extending the dicing tape. Becausethe passing-through groove is formed not by mechanically cutting thesemiconductor substrate but by etching which is a chemical reaction, theprecision of the cut surface is significantly improved. By operating thedicing saw in a direction perpendicular to the direction of arrangementof the passing-through grooves in arrays as shown by heavy lines in FIG.16, division into individual chips is carried out. It is to be notedthat a section between C1 and C2 in FIG. 16A which is an enlarged viewof FIG. 16 is, for example, the chip illustrated in FIG. 15.

FIG. 17A illustrates a structure where a driver circuit is formed on asilicon substrate. FIG. 17B is a plan view where such driving circuitchips including shift resisters, latches, and the like are arranged on awafer surface. In FIGS. 17A and 17B, a reference numeral 1700 denotes asilicon substrate, a reference numeral 1701 denotes an insulating filmformed of SiO₂, a reference numeral 1702 denotes a wire bonding pad, areference numeral 1703 denotes a MOS transistor forming the drivingcircuit, a reference numeral 1704 denotes a silicon wafer, and areference numeral 1705 denotes a driving circuit chip.

As illustrated in FIG. 18, first, a silicon driving circuit chip 1822,an enlarged view of which is shown in FIG. 18A, is cut out from asilicon wafer 1800 by a dicing saw, and an LED chip 1821, an enlargedview of which is shown in FIG. 18B, is cut out from a silicon wafer 1820by a dicing saw. The dicing is preferably carried out with the rearsurface of the second substrate being bonded to a dicing tape.

Then, die bonding of the silicon driving circuit chip 1822 and the LEDchip 1821 to a print substrate 1830 is carried out to electricallyconnect the silicon driving circuit chip 1822 and the LED chip 1821 bywire bonding. After that, the print substrate 1830 and the drivercircuit of the silicon driving circuit chip 1822 are connected with eachother by wire bonding. Further, a light amount variation correctioncircuit IC is added to obtain an LED array.

Although representative embodiments and an example of the presentinvention are described in the above, various variations of the presentembodiment and the present example are possible, and various replacementand modifications are possible which fall within the gist and scope ofthe present invention defined by the claims of the present application.

According to the present example, by using a silicon substrate with apassing-through groove, the number of bonding processes for transferringa compound semiconductor multilayer film onto a silicon substrate can besignificantly decreased compared with that in Japanese Patent Laid-OpenApplication No. 2005-012034 described in the above. Remarkable effectsattributable to improvement in the device yield and decrease in thenumber of processes are expected.

INDUSTRIAL APPLICABILITY

The present invention can be used for an array device wheresemiconductor devices are formed in an array on a semiconductorsubstrate, in particular, for an LED printer, a display, a device foroptical transmission and reception, or a light-receiving device using anLED device formed on a semiconductor substrate. When it is used in alight-receiving device, a scanner can be formed. When thelight-receiving device is used together with an LED array head, ascanner with a built-in illumination system is manufactured.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of theappended claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2006-293306, filed Oct. 27, 2006, and No. 2006-311625, filed Nov. 17,2006 which are hereby incorporated by reference herein in theirentirety.

1-29. (canceled)
 30. A method of manufacturing a semiconductor articlecomprising the steps of: preparing a first structure comprising a firstsemiconductor substrate, a compound semiconductor multilayer film, andan etching sacrificial layer provided between the first semiconductorsubstrate and the compound semiconductor multilayer film; preparing asecond structure comprising a second semiconductor substrate and aninsulating layer; bonding the first structure and the second structure;forming a second groove in the second semiconductor substrate; forming athird groove in the insulating layer through the second groove; forminga first groove in the compound semiconductor multilayer film through thesecond and third grooves so as to expose the etching sacrificial layer;and etching the etching sacrificial layer through the first, second, andthird grooves so as to separate the first semiconductor substrate.
 31. Amethod of manufacturing a semiconductor article according to claim 30,wherein an etching stop layer for stopping etching of the firstsemiconductor substrate is provided between the first semiconductorsubstrate and the etching sacrificial layer.
 32. A method ofmanufacturing a semiconductor article according to claim 30, wherein acircuit layer is provided on the surface of the second semiconductorsubstrate.
 33. A method of manufacturing a semiconductor articleaccording to claim 30, wherein the etching sacrificial layer and thecompound semiconductor multilayer film are alternately repeatedlylaminated on the first semiconductor substrate.
 34. A method ofmanufacturing a semiconductor article according to claim 31, wherein theetching stop layer, the etching sacrificial layer, and the compoundsemiconductor multilayer film are alternately repeatedly laminated onthe first semiconductor substrate.
 35. A method of manufacturing asemiconductor article according to claim 30, wherein at least one of ametal film and a DBR mirror is provided between the compoundsemiconductor multilayer film and the insulating layer.
 36. A method ofmanufacturing a semiconductor article according to claim 30, wherein theinsulating layer is made of a polyimide insulating material.
 37. Amethod of manufacturing a semiconductor article according to claim 30,wherein the second semiconductor substrate comprises a driver circuitfor driving a light-emitting device formed so as to include the compoundsemiconductor multilayer film.
 38. A method of manufacturing asemiconductor article according to claim 30, wherein the first groove isprovided in the compound semiconductor multilayer film such that thecompound semiconductor multilayer film is divided in an island shape,and wherein the method further comprises a step of forming alight-emitting device using the compound semiconductor multilayer filmon the second semiconductor substrate.
 39. A method of manufacturing asemiconductor article according to claim 30, wherein: the compoundsemiconductor multilayer film comprises a light-emitting layer; thefirst structure further comprises a DBR layer formed on the compoundsemiconductor multilayer film; the light-emitting layer is divided intoan array of a plurality of light-emitting portions; and a semiconductorcircuit is formed on the second semiconductor substrate, and wherein themethod further comprises a step of electrically connecting the pluralityof light-emitting portions with an electrode portion of thesemiconductor circuit for controlling light emission of thelight-emitting portions.
 40. A method of manufacturing a semiconductorarticle according to claim 38, wherein the island-shaped compoundsemiconductor multilayer film formed on the first semiconductorsubstrate surrounded by the first groove has a rectangle shape having along side and a short side, and a plurality of the second groovespassing through the second semiconductor substrate are intermittentlydisposed in an array in parallel with the direction of the long side(longitudinal direction) thereof.
 41. A method of manufacturing asemiconductor article according to claim 38, further comprising thesteps of: forming an electrode on the island-shaped compoundsemiconductor multilayer film via an insulating member to form alight-emitting device array chip having a long side direction and ashort side direction, after separating the first semiconductorsubstrate; and cutting the second semiconductor substrate in a directionof the long side so that the second grooves in parallel with one anotherwhich are provided in the second semiconductor substrate and arearranged in the direction of the short side are connected to each other.42. A method of manufacturing a semiconductor article according to claim30, wherein the top view of the shape of the compound semiconductormultilayer film patterned in an island shape by the first groove is arectangle having a long side direction and a short side direction, andwherein a plurality of the second grooves passing through the secondsemiconductor substrate is formed so as to be in parallel in thedirection of the long side to thereby form a passing-through groovegroup in the direction of the long side, in which a plurality of thepassing-through groove groups in the direction of the long side isarranged so as to be in parallel with one another at intervals which areequal to or longer than the length of the short side of theisland-shaped compound semiconductor multilayer film.
 43. A method ofmanufacturing a semiconductor article according to claim 30, wherein areflector is provided between the compound semiconductor multilayer filmand the second semiconductor substrate.